Embedded computing device

ABSTRACT

According to an example aspect of the present invention, there is provided an apparatus comprising a first processing core configured to generate first control signals and to control a display by providing the first control signals to the display via a first display interface, a second processing core configured to generate second control signals and to control the display by providing the second control signals to the display via a second display interface, and the first processing core being further configured to cause the second processing core to enter and leave a hibernation state.

FIELD OF INVENTION

The present invention in general relates, for example, to implementingmulti-core or multi-chip embedded solutions.

BACKGROUND OF INVENTION

Embedded devices generally comprise objects that contain an embeddedcomputing system, which may be enclosed by the object. The embeddedcomputer system may be designed with a specific use in mind, or theembedded computer system may be at least in part general-purpose in thesense that a user may be enabled to install software in it. An embeddedcomputer system may be based on a microcontroller or microprocessor CPU,for example.

Embedded devices may comprise one or more processors, user interfacesand displays, such that a user may interact with the device using theuser interface. The user interface may comprise buttons, for example. Anembedded device may comprise a connectivity function configured tocommunicate with a communications network, such as, for example, awireless communications network. The embedded device may be enabled toreceive from such a communications network information relating to, forexample, a current time and current time zone.

More complex embedded devices, such as cellular telephones, may allow auser to install applications into a memory, such as, for example, asolid-state memory, comprised in the device. Embedded devices arefrequently resource-constrained when compared to desktop or laptopcomputers. For example, memory capacity may be more limited than indesktop or laptop computers, processor computational capacity may belower and energy may be available from a battery. The battery, which maybe small, may be rechargeable.

Conserving battery power is a key task in designing embedded devices. Alower current usage enables longer time intervals in-between batterycharging. For example, smartphones benefit greatly when they can survivean entire day before needing recharging, since users are thereby enabledto recharge their phones overnight, and enjoy uninterrupted use duringthe day.

Battery resources may be conserved by throttling a processor clockfrequency between a maximum clock frequency and a lower clock frequency,for example one half of the maximum clock frequency. Another way toconserve battery power is to cause a display of an embedded device toswitch itself off then the device is not used, since displaying contenton a display consumes energy in order to cause the display to emit lightthat humans can see.

SUMMARY OF THE INVENTION

The invention is defined by the features of the independent claims. Somespecific embodiments are defined in the dependent claims.

According to a first aspect of the present invention, there is providedan apparatus comprising a first processing core configured to generatefirst control signals and to control a display by providing the firstcontrol signals to the display via a first display interface, a secondprocessing core configured to generate second control signals and tocontrol the display by providing the second control signals to thedisplay via a second display interface, and the first processing corebeing further configured to cause the second processing core to enterand leave a hibernation state.

Various embodiments of the first aspect may comprise at least onefeature from the following bulleted list:

-   -   the first processing core is electrically interfaced with at        least one of: a user interface, a wireless communications port,        a wired communications port, satellite positioning circuitry, a        magnetometer, a gyroscope, an accelerometer and a pressure        sensor    -   the second processing core is electrically interfaced with at        least one of: cellular communication circuitry, non-cellular        wireless communication circuitry and a second wired        communications port    -   the first processing core and the second processing core are        both electrically interfaced with a shared random access memory    -   the first processing core is configured to cause the second        processing core to leave the hibernation state responsive to a        determination that at least one of a first graphics mode not        supported by the first processing core is requested to be        provided to the display and a need for the second processing        core is predicted to occur    -   the first processing core is configured to cause the second        processing core to leave the hibernation state responsive to a        determination that a communications capability of the second        processing core is requested    -   the first processing core is configured to cause the second        processing core to enter the hibernation state responsive to a        determination that a second graphics mode, which is supported by        the first processing core, is requested to be provided to the        display    -   the second graphics mode comprises a reduced map view graphics        mode    -   the first processing core is configured to cause the second        processing core to enter the hibernation state responsive to a        determination that a user interface type not supported by the        first processing core is no longer requested    -   the apparatus comprises the display, the display having a first        electrical connection to the first display interface in the        first processing core and a second electrical connection to the        second display interface in the second processing core    -   the first processing core and the second processing core are        comprised in a same integrated circuit    -   the first processing core is comprised in a microcontroller and        the second processing core is comprised in a microprocessor, the        microcontroller being external to the microprocessor and the        microprocessor being external to the microcontroller    -   the apparatus is configured to store, at least in part, a        context of the second processing core in connection with        transitioning the second processing core into the hibernation        state.

According to a second aspect of the present invention, there is provideda method, comprising generating, by a first processing core, firstcontrol signals, controlling a display by providing the first controlsignals to the display via a first display interface, generating, by asecond processing core, second control signals, controlling the displayby providing the second control signals to the display via a seconddisplay interface, and causing the second processing core to enter andleave a hibernation state.

Various embodiments of the first aspect may comprise at least onefeature from the following bulleted list:

-   -   the first processing is core electrically interfaced with at        least one of: a user interface, a wireless communications port,        a wired communications port, satellite positioning circuitry, a        magnetometer, a gyroscope, an accelerometer and a pressure        sensor    -   the second processing core is electrically interfaced with at        least one of: cellular communication circuitry, non-cellular        wireless communication circuitry and a second wired        communications port    -   the first processing core and the second processing core are        both electrically interfaced with a shared random access memory    -   the method further comprises causing, by the first processing        core, the second processing core to leave the hibernation state        responsive to a determination that a first graphics mode not        supported by the first processing core is requested to be        provided to the display    -   the method further comprised causing, by the first processing        core, the second processing core to leave the hibernation state        responsive to a determination that a communications capability        of the second processing core is requested    -   the method further comprises causing, by the first processing        core, the second processing core to enter the hibernation state        responsive to a determination that a second graphics mode, which        is supported by the first processing core, is requested to be        provided to the display    -   the second graphics mode comprises a reduced map view graphics        mode    -   the method further comprises causing, by the first processing        core, the second processing core to enter the hibernation state        responsive to a determination that a user interface type not        supported by the first processing core is no longer requested    -   the method is performed in an apparatus comprising the display,        the display having a first electrical connection to the first        display interface in the first processing core and a second        electrical connection to the second display interface in the        second processing core    -   the first processing core and the second processing core are        comprised in a same integrated circuit    -   the first processing core is comprised in a microcontroller and        the second processing core is comprised in a microprocessor, the        microcontroller being external to the microprocessor and the        microprocessor being external to the microcontroller.

According to a third aspect of the present invention, there is providedan apparatus comprising at least one processing core and at least onememory including computer program code, the at least one memory and thecomputer program code being configured to, with the at least oneprocessing core, cause the apparatus at least to generate, by a firstprocessing core, first control signals, control a display by providingthe first control signals to the display via a first display interface,generate, by a second processing core, second control signals, controlthe display by providing the second control signals to the display via asecond display interface, and cause the second processing core to enterand leave a hibernation state.

According to a fourth aspect of the present invention, there is providedan apparatus comprising means for generating, by a first processingcore, first control signals, means for controlling a display byproviding the first control signals to the display via a first displayinterface, means for generating, by a second processing core, secondcontrol signals, means for controlling the display by providing thesecond control signals to the display via a second display interface,and means for causing the second processing core to enter and leave ahibernation state.

According to a fifth aspect of the present invention, there is provideda non-transitory computer readable non-transitory medium having storedthereon a set of computer readable instructions that, when executed byat least one processor, cause an apparatus to at least generate, by afirst processing core, first control signals, control a display byproviding the first control signals to the display via a first displayinterface, generate, by a second processing core, second controlsignals, control the display by providing the second control signals tothe display via a second display interface, and cause the secondprocessing core to enter and leave a hibernation state.

According to a sixth aspect of the present invention, there is provideda computer program configured to cause a method in accordance with thesecond aspect to be performed, when run.

INDUSTRIAL APPLICABILITY

At least some embodiments of the present invention find industrialapplication in embedded multi-chip or multi-core and power usageoptimization thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example system capable of supporting at least someembodiments of the present invention;

FIG. 2 illustrates a first example apparatus capable of supporting atleast some embodiments of the present invention;

FIG. 3 illustrates a second example apparatus capable of supporting atleast some embodiments of the present invention;

FIG. 4 illustrates signalling in accordance with at least someembodiments of the present invention;

FIG. 5 is a first flow chart of a first method in accordance with atleast some embodiments of the present invention, and

FIG. 6 is a state transition diagram in accordance with at least someembodiments of the present invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

Furnishing an embedded device with two or more processor cores, at leastsome of which are enabled to control the display of the device, makespossible power savings where a less-capable processor core is configuredto toggle a more capable processor core to and from a hibernation state.A hibernation state may comprise that a clock frequency of the morecapable processing core is set to zero, for example. In a hibernationstate, in addition to, or alternatively to, setting the clock frequencyof the more capable processing core to zero, a memory refresh rate ofmemory used by the more capable core may be set to zero. Alternativelyto zero, a low non-zero frequency may be used for the clock frequencyand/or the memory refresh frequency. In some embodiments, a more capableprocessing core may employ a higher-density memory technology, such asdouble data rate, DDR, memory, and a less capable processing core mayemploy a lower-density memory technology, such as static random accessmemory, SRAM, memory. In a hibernation state the hibernated processingcore, or more generally processing unit, may be powered off.Alternatively to a processor core, an entire processor may, in someembodiments, be transitioned to a hibernation state. An advantage ofhibernating an entire processor is that circuitry in the processoroutside the core is also hibernated, further reducing currentconsumption.

FIG. 1 illustrates an example system capable of supporting at least someembodiments of the present invention. In the example system of FIG. 1 iscomprised device 110, which may comprise an embedded device, such as forexample a smart watch, personal health monitor, cellular phone,smartphone or other suitable device.

Device 110 is in the example of FIG. 1 configured with a plurality ofcommunication interfaces. A first communication interface enables device110 to receive satellite positioning information from satelliteconstellation 140, via satellite link 114. Examples of suitablesatellite positioning constellations include global positioning system,GPS, GLONASS, Beidou and the Galileo satellite positioningconstellation.

A second communications interface enables device 110 to communicate witha cellular communications system, such as for example a wideband codedivision multiple access, WCDMA, or long term evolution, LTE, network. Acellular link 112 may be configured to convey information between device110 and base station 120. The cellular link 112 may be configured inaccordance with the same cellular communications standard that bothdevice 110 and base station 120 both support. Base station 120 may becomprised in a cellular radio access network that comprises a pluralityof base stations. Base station 120 may be arranged to communicate withcore network node 150 via connection 125. Core network node 150 maycomprise a switch, mobility management entity or gateway, for example.Core network node 150 may be arranged to communicate with a furthernetwork 170, such as for example the Internet, via connection 157.

A third communications interface enables device 110 to communicate witha non-cellular communications system, such as for example a wirelesslocal area network, WLAN, Bluetooth or worldwide interoperability formicrowave access, WiMAX, system. A further example is an inductiveunderwater communication interface. A non-cellular link 113 may beconfigured to convey information between device 110 and access point130. The non-cellular link 113 may be configured in accordance with thesame non-cellular technology that both device 110 and access point 130both support. Access point 130 may be arranged to communicate withgateway 160 via connection 136. Gateway 160 may be arranged tocommunicate with further network 170 via connection 167. Each ofconnections 125, 157, 136 and 167 may be wire-line or at least in partwireless. Not all of these connections need to be of the same type. Incertain embodiments, at least one of the first communications interface,the second communications interface and the third communicationsinterface is absent.

A fourth communications link may enable device 110 to communicate with amobile device. For example, a low-power wireless interface may enablecommunication with a mobile device where device 110 lacks cellularcapability and a mobile device distinct from device 110 has cellularcapability. An example of a low-power wireless interface isBluetooth-low energy, BLE, or Bluetooth Smart.

In use, device 110 may use satellite positioning information fromsatellite constellation 140 to determine a geo-location of device 110.The geo-location may be determined in terms of coordinates, for example.Device 110 may be configured to present, on a display that may becomprised in device 110, a map with the determined geo-location ofdevice 110 presented thereon. For example, device 110 may display astreet or feature map of the surroundings, with a symbol denoting thecurrent location of device 110 on the map. Providing a map with acurrent location of device 110 indicated thereon, and/or providingnavigation instructions, may be referred to as a mapping service.

In some embodiments, device 110 may provide connectivity services to auser, such as for example web browsing, instant messaging and/or email.Device 110 may be configured to provide connectivity service to itsfunctions and/or applications, in some embodiments including enablingremote access to these functions and/or services over a network, such asthe Internet. Thus device 110 may be trackable over the Internet, forexample. Such connectivity services may be run over bidirectionalcommunication links, such as for example cellular link 112 and/ornon-cellular link 113. In general, device 110 may provide a service,such as for example a mapping service or a connectivity service, to auser via a display.

Device 110 may comprise two or more processing units. The two or moreprocessing units may each comprise a processing core. Each processingunit may comprise one or multiple uniformal or heterogeneous processorcores and/or different volatile and non-volatile memories. For example,device 110 may comprise a microprocessor with at least one processingcore, and a microcontroller with at least one processing core. Theprocessing cores needn't be of the same type, for example, a processingcore in a microcontroller may have more limited processing capabilityand/or a less capable memory technology than a processing core comprisedin a microprocessor. In some embodiments, a single integrated circuitcomprises two processing cores, a first one of which has lesserprocessing capability and consumes less power, and a second one of whichhas greater processing capability and consumes more power. In general afirst one of the two processing units may have lesser processingcapability and consume less power, and a second one of the twoprocessing units may have greater processing capability and consume morepower. Each of the processing units may be enabled to control thedisplay of device 110. The more capable processing unit may beconfigured to provide a richer visual experience via the display. Theless capable processing unit may be configured to provide a reducedvisual experience via the display. An example of a reduced visualexperience is a reduced colour display mode, as opposed to a rich colourdisplay mode. An another example of a reduced visual experience is onewhich is black-and-white. An example of a richer visual experience isone which uses colours. Colours may be represented with 16 bits or 24bits, for example.

Each of the two processing units may comprise a display interfaceconfigured to communicate toward the display. For example, where theprocessing units comprise a microprocessor and a microcontroller, themicroprocessor may comprise transceiver circuitry coupled to at leastone metallic pin under the microprocessor, the at least one metallic pinbeing electrically coupled to an input interface of a display controldevice. The display control device, which may be comprised in thedisplay, is configured to cause the display to display information independence of electrical signals received in the display control device.Likewise the microcontroller in this example may comprise transceivercircuitry coupled to at least one metallic pin under themicrocontroller, the at least one metallic pin being electricallycoupled to an input interface of a display control device. The displaycontrol device may comprise two input interfaces, one coupled to each ofthe two processing units, or alternatively the display control devicemay comprise a single input interface into which both processing unitsare enabled to provide inputs via their respective display interfaces.Thus a display interface in a processing unit may comprise transceivercircuitry enabling the processing unit to transmit electrical signalstoward the display.

One of the processing units, for example the less capable or the morecapable one, may be configured to control, at least in part, the otherprocessing unit. For example, the less capable processing unit, forexample a less capable processing core, may be enabled to cause the morecapable processing unit, for example a more capable processing core, totransition into and from a hibernating state. These transitions may becaused to occur by signalling via an inter-processing unit interface,such as for example an inter-core interface.

When transitioning into a hibernating state from an active state, thetransitioning processing unit may store its context, at least in part,into a memory, such as for example a pseudostatic random access memory,PSRAM, SRAM, FLASH or ferroelectric RAM, FRAM. The context may comprise,for example, content of registers and/or addressing. When transitioningfrom a hibernated state using a context stored in memory, a processingunit may resume processing faster and/or from a position where theprocessing unit was when it was hibernated. This way, a delayexperienced by a user may be minimised. Alternative terms occasionallyused for context include state and image. In a hibernating state, aclock frequency of the processing unit and/or an associated memory maybe set to zero, meaning the processing unit is powered off and does notconsume energy. Circuitry configured to provide an operating voltage toat least one processing unit may comprise a power management integratedcircuit, PMIC, for example. Since device 110 comprises anotherprocessing unit, the hibernated processing unit may be poweredcompletely off while maintaining usability of device 110.

When transitioning from a hibernated state to an active state, thetransitioning processing unit may have its clock frequency set to anon-zero value. The transitioning processing unit may read a contextfrom a memory, wherein the context may comprise a previously storedcontext, for example a context stored in connection with transitioninginto the hibernated state, or the context may comprise a default stateor context of the processing unit stored into the memory in the factory.The memory may comprise pseudostatic random access memory, SRAM, FLASHand/or FRAM, for example. The memory used by the processing unittransitioning to and from the hibernated state may comprise DDR memory,for example.

With one processing unit in a hibernation state, the non-hibernatedprocessing unit may control device 110. For example, the non-hibernatedprocessing unit may control the display via the display interfacecomprised in the non-hibernated processing unit. For example, where aless capable processing unit has caused a more capable processing unitto transition to the hibernated state, the less capable processing unitmay provide a reduced user experience, for example, via at least inpart, the display. An example of a reduced user experience is a mappingexperience with a reduced visual experience comprising a black-and-whiterendering of the mapping service. The reduced experience may besufficient for the user to obtain a benefit from it, with the advantagethat battery power is conserved by hibernating the more capableprocessing unit. In some embodiments, a more capable processing unit,such as a microprocessor, may consume a milliampere of current when in anon-hibernated low-power state, while a less capable processing unit,such as a microcontroller, may consume only a microampere when in anon-hibernated low-power state. In non-hibernated states currentconsumption of processing units may be modified by setting an operatingclock frequency to a value between a maximum clock frequency and aminimum non-zero clock frequency. In at least some embodiments,processing units, for example less capable processing units, may beconfigurable to power down for short periods, such as 10 or 15microseconds, before being awakened. In the context of this document,this is not referred to as a hibernated state but an active low-powerconfiguration. An average clock frequency calculated over a few suchperiods and the intervening active periods is a positive non-zero value.A more capable processing unit may be enabled to run the Androidoperating system, for example.

Triggering events for causing a processing unit to transition to thehibernated state include a user indicating a non-reduced experience isno longer needed, a communication interface of the processing unit nolonger being needed and device 110 not having been used for apredetermined length of time. An example indication that a non-reducedexperience is no longer needed is where the user deactivates a fullversion of an application, such as for example a mapping application.Triggering events for causing a processing unit to transition from thehibernated state to an active state may include a user indicating anon-reduced experience is needed, a communication interface of theprocessing unit being requested and device 110 being interacted withafter a period of inactivity. Alternatively or additionally, externalevents may be configured as triggering events, such as, for example,events based on sensors comprised in device 110. An example of such anexternal event is a clock-based event which is configured to occur at apreconfigured time of day, such as an alarm clock function, for example.In at least some embodiments, the non-reduced experience comprises useof a graphics mode the non-hibernated processing unit cannot support,but the hibernated processing unit can support. A graphics mode maycomprise a combination of a resolution, colour depth and/or refreshrate, for example.

In some embodiments, a user need or user request for the non-reducedexperience may be predicted. Such predicting may be based at least inpart on a usage pattern of the user, where the user has tended toperform a certain action in the reduced experience before requesting thenon-reduced experience. In this case, responsive to a determination theuser performs the certain action in the reduced experience, thenon-reduced mode may be triggered.

If the processing units reside in separate devices or housings, such asa wrist-top computer and a handheld or fixedly mounted display devicefor example, a bus may be implemented in a wireless fashion by using awireless communication protocol. Radio transceiver units functionallyconnected to their respective processing units may thus perform thefunction of the bus, forming a personal area network, PAN. The wirelesscommunication protocol may be one used for communication betweencomputers, and/or between any remote sensors, such as a Bluetooth LE orthe proprietary ANT+ protocol. These are using direct-sequence spreadspectrum, DSSS, modulation techniques and an adaptive isochronousnetwork configuration, respectively. Enabling descriptions of necessaryhardware for various implementations for wireless links are available,for example, from the Texas Instrument®'s handbook “WirelessConnectivity” which includes IC circuits and related hardwareconfigurations for protocols working in sub-1- and 2.4-GHz frequencybands, such as ANT™, Bluetooth®, Bluetooth® low energy, RFID/NFC,PurePath™ Wireless audio, ZigBee®, IEEE 802.15.4, ZigBee RF4CE, 6LoWPAN,Wi-Fi®.

In connection with hibernation, the PAN may be kept in operation by thenon-hibernated processing unit, such that when hibernation ends, theprocessing unit leaving the hibernated mode may have access to the PANwithout needing to re-establish it.

FIG. 2 illustrates a first example apparatus capable of supporting atleast some embodiments of the present invention. The illustratedapparatus comprises a microcontroller 210 and a microprocessor 220.Microcontroller 210 may comprise, for example, a Silabs EMF32 or aRenesas RL78 microcontroller, or similar. Microprocessor 220 maycomprise, for example, a Qualcomm Snapdragon processor or an ARMCortex-based processor. Microcontroller 210 and microprocessor 220 arein the example of FIG. 2 communicatively coupled with an inter-coreinterface, which may comprise, for example, a serial or a parallelcommunication interface. More generally an interface disposed betweenmicrocontroller 210 and microprocessor 220 may be considered aninter-processing unit interface.

Microcontroller 210 is communicatively coupled, in the illustratedexample, with a buzzer 270, a universal serial bus, USB, interface 280,a pressure sensor 290, an acceleration sensor 2100, a gyroscope 2110, amagnetometer 2120, satellite positioning circuitry 2130, a Bluetoothinterface 2140, user interface buttons 2150 and a touch interface 2160.Pressure sensor 290 may comprise an atmospheric pressure sensor, forexample.

Microprocessor 220 is communicatively coupled with an optional cellularinterface 240, a non-cellular interface 250 and a USB interface 260.Microprocessor 220 is further communicatively coupled, viamicroprocessor display interface 222, with display 230. Microcontroller210 is likewise communicatively coupled, via microcontroller displayinterface 222, with display 230. Microprocessor display interface 222may comprise communication circuitry comprised in microprocessor 220.Microcontroller display interface 212 may comprise communicationcircuitry comprised in microcontroller 210.

Microcontroller 210 may be configured to determine whether triggeringevents occur, wherein responsive to the triggering eventsmicrocontroller 210 may be configured to cause microprocessor 220 totransition into and out of the hibernating state described above. Whenmicroprocessor 220 is in the hibernating state, microcontroller 210 maycontrol display 230 via microcontroller display interface 222.Microcontroller 210 may thus provide, when microprocessor 220 ishibernated, for example, a reduced experience to a user via display 230.

Responsive to a triggering event, microcontroller 210 may causemicroprocessor 220 to transition from the hibernated state to an activestate. For example, where a user indicates, for example via buttons2150, that he wishes to originate a cellular communication connection,microcontroller 210 may cause microprocessor 220 to transition to anactive state since cellular interface 240 is controllable bymicroprocessor 220, but, in the example of FIG. 2, not directly usableby microcontroller 210. In some embodiments, when microprocessor 220 ishibernated, also cellular interface 240 is in a hibernated state.Cellular interface 240 may comprise an electrical interface to acellular transceiver, for example. Cellular interface 240 may comprisecontrol circuitry of a cellular transceiver.

In various embodiments, at least two elements illustrated in FIG. 2 maybe integrated on a same integrated circuit. For example, microprocessor220 and microcontroller 210 may be disposed as processing cores in asame integrated circuit. Where this is the case, for example, cellularinterface 240 may be a cellular interface of this integrated circuit,comprised in this integrated circuit, with cellular interface 240 beingcontrollable by microprocessor 220 but not by microcontroller 210. Inother words, individual hardware features of the integrated circuit maybe controllable by one of microcontroller 210 and microprocessor 220,but not both. On the other hand, some hardware features may becontrollable by either processing unit. For example, USB interface 260and USB interface 280 may be in such an integrated embodiment one andthe same USB interface of the integrated circuit, controllable by eitherprocessing core.

In FIG. 2 are further illustrated memory 2170 and memory 2180. Memory2170 is used by microprocessor 220, and may be based on a DDR memorytechnology, such as for example DDR2 or DDR3, for example. Memory 2180is used by microcontroller 210, and may be based on SRAM technology, forexample.

FIG. 3 illustrates a second example apparatus capable of supporting atleast some embodiments of the present invention.

Illustrated is device 300, which may comprise, for example, an embeddeddevice 110 of FIG. 1. Comprised in device 300 is processor 310, whichmay comprise, for example, a single- or multi-core processor wherein asingle-core processor comprises one processing core and a multi-coreprocessor comprises more than one processing core. Processor 310 maycorrespond to the structure illustrated in FIG. 2, with the exception ofdisplay 230, for example. Processor 310 may comprise more than oneprocessor or processing unit. Processor 310 may comprise at least oneapplication-specific integrated circuit, ASIC. Processor 310 maycomprise at least one field-programmable gate array, FPGA. Processor 310may be means for performing method steps in device 300. Processor 310may be configured, at least in part by computer instructions, to performactions.

Device 300 may comprise memory 320. Memory 320 may compriserandom-access memory and/or permanent memory. Memory 320 may comprisevolatile and/or non-volatile memory. Memory 320 may comprise at leastone RAM chip. Memory 320 may comprise magnetic, optical and/orholographic memory, for example. Memory 320 may be at least in partaccessible to processor 310. Memory 320 may be means for storinginformation. Memory 320 may comprise computer instructions thatprocessor 310 is configured to execute. When computer instructionsconfigured to cause processor 310 to perform certain actions are storedin memory 320, and device 300 overall is configured to run under thedirection of processor 310 using computer instructions from memory 320,processor 310 and/or its at least one processing core may be consideredto be configured to perform said certain actions. Memory 320 may be atleast in part comprised in processor 310. Memory 320 may be at least inpart external to device 300 but accessible to device 300.

Device 300 may comprise a transmitter 330. Device 300 may comprise areceiver 340. Transmitter 330 and receiver 340 may be configured totransmit and receive, respectively, information in accordance with atleast one cellular or non-cellular standard. Transmitter 330 maycomprise more than one transmitter. Receiver 340 may comprise more thanone receiver. Transmitter 330 and/or receiver 340 may be configured tooperate in accordance with global system for mobile communication, GSM,wideband code division multiple access, WCDMA, long term evolution, LTE,IS-95, wireless local area network, WLAN, Ethernet and/or worldwideinteroperability for microwave access, WiMAX, standards, for example.Transmitter 330 and/or receiver 340 may be controllable via cellularinterface 240, non-cellular interface 250 and/or USB interface 280 ofFIG. 2, for example.

Device 300 may comprise a near-field communication, NFC, transceiver350. NFC transceiver 350 may support at least one NFC technology, suchas NFC, Bluetooth, Wibree or similar technologies.

Device 300 may comprise user interface, UI, 360. UI 360 may comprise atleast one of a display, a keyboard, a touchscreen, a vibrator arrangedto signal to a user by causing device 300 to vibrate, a speaker and amicrophone. User input to UI 360 may be based on patterns, such as, forexample, where a user shakes device 300 to initiate actions via UI 360.A user may be able to operate device 300 via UI 360, for example toaccept incoming telephone calls, to originate telephone calls or videocalls, to browse the Internet, to manage digital files stored in memory320 or on a cloud accessible via transmitter 330 and receiver 340, orvia NFC transceiver 350, and/or to play games. UI 360 may comprise, forexample, buttons 2150 and display 230 of FIG. 2.

Device 300 may comprise or be arranged to accept a user identity module370. User identity module 370 may comprise, for example, a subscriberidentity module, SIM, card installable in device 300. A user identitymodule 370 may comprise information identifying a subscription of a userof device 300. A user identity module 370 may comprise cryptographicinformation usable to verify the identity of a user of device 300 and/orto facilitate encryption of communicated information and billing of theuser of device 300 for communication effected via device 300.

Processor 310 may be furnished with a transmitter arranged to outputinformation from processor 310, via electrical leads internal to device300, to other devices comprised in device 300. Such a transmitter maycomprise a serial bus transmitter arranged to, for example, outputinformation via at least one electrical lead to memory 320 for storagetherein. Alternatively to a serial bus, the transmitter may comprise aparallel bus transmitter. Likewise processor 310 may comprise a receiverarranged to receive information in processor 310, via electrical leadsinternal to device 300, from other devices comprised in device 300. Sucha receiver may comprise a serial bus receiver arranged to, for example,receive information via at least one electrical lead from receiver 340for processing in processor 310. Alternatively to a serial bus, thereceiver may comprise a parallel bus receiver.

Device 300 may comprise further devices not illustrated in FIG. 3. Forexample, where device 300 comprises a smartphone, it may comprise atleast one digital camera. Some devices 300 may comprise a back-facingcamera and a front-facing camera, wherein the back-facing camera may beintended for digital photography and the front-facing camera for videotelephony. Device 300 may comprise a fingerprint sensor arranged toauthenticate, at least in part, a user of device 300. In someembodiments, device 300 lacks at least one device described above. Forexample, some devices 300 may lack a NFC transceiver 350 and/or useridentity module 370.

Processor 310, memory 320, transmitter 330, receiver 340, NFCtransceiver 350, UI 360 and/or user identity module 370 may beinterconnected by electrical leads internal to device 300 in a multitudeof different ways. For example, each of the aforementioned devices maybe separately connected to a master bus internal to device 300, to allowfor the devices to exchange information. However, as the skilled personwill appreciate, this is only one example and depending on theembodiment various ways of interconnecting at least two of theaforementioned devices may be selected without departing from the scopeof the present invention.

FIG. 4 illustrates signalling in accordance with at least someembodiments of the present invention. On the vertical axes are disposed,from left to right, user interface UI, processing unit PU1, processingunit 2 PU2, and finally display DISP. Time advances from the top towardthe bottom. Processing unit 2 may have higher processing capability, andbe associated with a higher current consumption, than processing unit 1.

In phase 410, processing unit 2, which may comprise a processing core,controls the display. For example, processing unit 2 may run anapplication and provide to the display instructions to displayinformation reflective of the state of the application.

In phase 420, processing unit 1 determines that a triggering eventoccurs, the triggering event being associated with a transition ofprocessing unit 2 from an active state to a hibernated state. Processingunit 1 may determine an occurrence of a triggering event by receivingfrom processing unit 2 an indication that a task performed by processingunit 2 has been completed, for example. As discussed above, thehibernating state may comprise that a clock frequency of processing unit2 is set to zero. Responsive to the determination of phase 420,processing unit 1 assumes control of the display in phase 430, andcauses processing unit 2 to transition to the hibernating state in phase440. Subsequently, in phase 450, processing unit 2 is in the hibernatedstate. When processing unit 2 is in the hibernated state, batteryresources of the device may be depleted at a reduced rate. In someembodiments, phase 430 may start at the same time as phase 440 occurs,or phase 440 may take place before phase 430 starts.

In phase 460, a user interacts with the user interface UI in such a waythat processing unit 1 determines a triggering event to transitionprocessing unit 2 from the hibernated state to an active state. Forexample, the user may trigger a web browser application that requires aconnectivity capability that only processing unit 2 can provide.Responsively, in phase 470 processing unit 1 causes processing unit 2 towake up from the hibernating state. As a response, processing unit 2 mayread a state from a memory and wake up to this state, and assume controlof the display, which is illustrated as phase 480.

FIG. 5 is a first flow chart of a first method in accordance with atleast some embodiments of the present invention. The phases of theillustrated method may be performed in device 110 of FIG. 1, or in theapparatus of FIG. 2, for example.

Phase 510 comprises generating, by a first processing core, firstcontrol signals. Phase 520 comprises controlling a display by providingthe first control signals to the display via a first display interface.Phase 530 comprises generating, by a second processing core, secondcontrol signals. Phase 540 comprises controlling the display byproviding the second control signals to the display via a second displayinterface. Finally, phase 550 comprises causing the second processingcore to enter and leave a hibernation state.

FIG. 6 is a state transition diagram in accordance with at least someembodiments of the present invention.

PU1 corresponds to processing unit 1, for example, a less capableprocessing unit. PU2 corresponds to processing unit 2, for example, amore capable processing unit. These units may be similar to those indiscussed in connection with FIG. 4, for example. In an initial state,the device comprising PU1 and PU2 is in an inactive state, with zerosindicating the states of both PU1 and PU2. PU1 and PU2 are both switchedoff.

Starting from the initial power-off state, first PU1 is powered up,indicated as a “1” in the state of PU1, while PU2 remains in an offstate, denoted by zero. Thus the compound state is “10”, correspondingto a case where PU1 is active and PU2 is not. In this state, the devicemay offer a reduced experience to a user and consume relatively littlecurrent from battery reserves.

In addition to, or alternatively to, a power-off state PU1 and/or PU2may have an intermediate low-power state from which it may betransitioned to an active state faster than from a complete power-offstate. For example, a processing unit may be set to such an intermediatelow-power state before being set to a power-off state. In case theprocessing unit is needed soon afterward, it may be caused to transitionback to the power-up state. If no need for the processing unit isidentified within a preconfigured time, the processing unit may becaused to transition from the intermediate low-power state to apower-off state.

Arrow 610 denotes a transition from state “10” to state “11”, in otherwords, a transition where PU2 is transitioned from the hibernated stateto an active state, for example, a state where its clock frequency isnon-zero. PU1 may cause the transition denoted by arrow 610 to occur,for example, responsive to a triggering event. In state “11”, the devicemay be able to offer a richer experience, at the cost of faster batterypower consumption.

Arrow 620 denotes a transition from state “11” to state “10”, in otherwords, a transition where PU2 is transitioned from an active state tothe hibernated state. PU1 may cause the transition denoted by arrow 620to occur, for example, responsive to a triggering event.

It is to be understood that the embodiments of the invention disclosedare not limited to the particular structures, process steps, ormaterials disclosed herein, but are extended to equivalents thereof aswould be recognized by those ordinarily skilled in the relevant arts. Itshould also be understood that terminology employed herein is used forthe purpose of describing particular embodiments only and is notintended to be limiting.

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure, orcharacteristic described in connection with the embodiment is includedin at least one embodiment of the present invention. Thus, appearancesof the phrases “in one embodiment” or “in an embodiment” in variousplaces throughout this specification are not necessarily all referringto the same embodiment.

As used herein, a plurality of items, structural elements, compositionalelements, and/or materials may be presented in a common list forconvenience. However, these lists should be construed as though eachmember of the list is individually identified as a separate and uniquemember. Thus, no individual member of such list should be construed as ade facto equivalent of any other member of the same list solely based ontheir presentation in a common group without indications to thecontrary. In addition, various embodiments and example of the presentinvention may be referred to herein along with alternatives for thevarious components thereof. It is understood that such embodiments,examples, and alternatives are not to be construed as de factoequivalents of one another, but are to be considered as separate andautonomous representations of the present invention.

Furthermore, described features, structures, or characteristics may becombined in any suitable or technically feasible manner in one or moreembodiments. In the following description, numerous specific details areprovided, such as examples of lengths, widths, shapes, etc., to providea thorough understanding of embodiments of the invention. One skilled inthe relevant art will recognize, however, that the invention can bepracticed without one or more of the specific details, or with othermethods, components, materials, etc. In other instances, well-knownstructures, materials, or operations are not shown or described indetail to avoid obscuring aspects of the invention.

While the forgoing examples are illustrative of the principles of thepresent invention in one or more particular applications, it will beapparent to those of ordinary skill in the art that numerousmodifications in form, usage and details of implementation can be madewithout the exercise of inventive faculty, and without departing fromthe principles and concepts of the invention. Accordingly, it is notintended that the invention be limited, except as by the claims setforth below.

The invention claimed is:
 1. An apparatus comprising: a first processingcore configured to generate first control signals and to control adisplay by providing the first control signals to the display via afirst display interface; a second processing core configured to generatesecond control signals and to control the display by providing thesecond control signals to the display via a second display interface,and the first processing core being further configured to cause thesecond processing core to enter and leave a hibernation state, whereinthe second processing core is electrically interfaced with cellularcommunication circuitry, wherein the first processing core is configuredto cause the second processing core to leave the hibernation stateresponsive to a determination that a communications capability of thesecond processing core is requested.
 2. The apparatus according to claim1, wherein the first processing core is electrically interfaced with atleast one of: a user interface, a wireless communications port, a wiredcommunications port, satellite positioning circuitry, a magnetometer, agyroscope, an accelerometer and a pressure sensor.
 3. The apparatusaccording to claim 1, wherein the second processing core is electricallyinterfaced with at least one of: non-cellular wireless communicationcircuitry and a second wired communications port.
 4. The apparatusaccording to claim 1, wherein the first processing core and the secondprocessing core are both electrically interfaced with a shared randomaccess memory.
 5. The apparatus according to claim 1, wherein the firstprocessing core is configured to cause the second processing core toleave the hibernation state responsive to a determination that a needfor the second processing core is predicted to occur.
 6. The apparatusaccording to claim 1, wherein the first processing core is configured tocause the second processing core to enter the hibernation stateresponsive to a determination that a second graphics mode, which issupported by the first processing core, is requested to be provided tothe display.
 7. The apparatus according to claim 6, wherein the secondgraphics mode comprises a reduced map view graphics mode.
 8. Theapparatus according to claim 1, wherein the first processing core isconfigured to cause the second processing core to enter the hibernationstate responsive to a determination that a user interface type notsupported by the first processing core is no longer requested.
 9. Theapparatus according to claim 1, wherein the apparatus comprises thedisplay, the display having a first electrical connection to the firstdisplay interface in the first processing core and a second electricalconnection to the second display interface in the second processingcore.
 10. The apparatus according to claim 1, wherein the firstprocessing core and the second processing core are comprised in a sameintegrated circuit.
 11. The apparatus according to claim 1, wherein thefirst processing core is comprised in a microcontroller and the secondprocessing core is comprised in a microprocessor, the microcontrollerbeing external to the microprocessor and the microprocessor beingexternal to the microcontroller.
 12. The apparatus according to claim 1,wherein the apparatus is configured to store, at least in part, acontext of the second processing core in connection with transitioningthe second processing core into the hibernation state.
 13. A method,comprising: generating, by a first processing core, first controlsignals; controlling a display by providing the first control signals tothe display via a first display interface; generating, by a secondprocessing core, second control signals; controlling the display byproviding the second control signals to the display via a second displayinterface; causing the second processing core to enter and leave ahibernation state, wherein the second processing core is electricallyinterfaced with cellular communication circuitry, wherein the firstprocessing core is configured to cause the second processing core toleave the hibernation state responsive to a determination that acommunications capability of the second processing core is requested.14. The method according to claim 13, wherein the first processing iscore electrically interfaced with at least one of: a user interface, awireless communications port, a wired communications port, satellitepositioning circuitry, a magnetometer, a gyroscope, an accelerometer anda pressure sensor.
 15. The method according to claim 13, wherein thesecond processing core is electrically interfaced with at least one of:non-cellular wireless communication circuitry and a second wiredcommunications port.
 16. The method according to claim 13, wherein thefirst processing core and the second processing core are bothelectrically interfaced with a shared random access memory.
 17. Themethod according to claim 13, further comprising causing, by the firstprocessing core, the second processing core to leave the hibernationstate responsive to a determination that a need for the secondprocessing core is predicted to occur.
 18. The method according to claim13, further comprising causing, by the first processing core, the secondprocessing core to enter the hibernation state responsive to adetermination that a second graphics mode, which is supported by thefirst processing core, is requested to be provided to the display. 19.The method according to claim 18, wherein the second graphics modecomprises a reduced map view graphics mode.
 20. The method according toclaim 13, further comprising causing, by the first processing core, thesecond processing core to enter the hibernation state responsive to adetermination that a user interface type not supported by the firstprocessing core is no longer requested.
 21. The method according toclaim 13, wherein the method is performed in an apparatus comprising thedisplay, the display having a first electrical connection to the firstdisplay interface in the first processing core and a second electricalconnection to the second display interface in the second processingcore.
 22. The method according to claim 13, wherein the first processingcore and the second processing core are comprised in a same integratedcircuit.
 23. A non-transitory computer readable non-transitory mediumhaving stored thereon a set of computer readable instructions that, whenexecuted by at least one processor, cause an apparatus to at least:generate, by a first processing core, first control signals; control adisplay by providing the first control signals to the display via afirst display interface; generate, by a second processing core, secondcontrol signals; control the display by providing the second controlsignals to the display via a second display interface; cause the secondprocessing core to enter and leave a hibernation state, wherein thesecond processing core is electrically interfaced with cellularcommunication circuitry, wherein the first processing core is configuredto cause the second processing core to leave the hibernation stateresponsive to a determination that a communications capability of thesecond processing core is requested.